Synthetic drying oils



Patented Dec. 20, 1949 2,491,496 SYNTHETIC DRYING onis Warren W.Johnstone, Riverside, Ill., assignor to Universal Oil Products Company,Chicago, 111., a corporation of Delaware No Drawing. ApplicationDecember 24, 1947, Serial No. 793,766

3 Claims. (01. 196-449) This application is a continuation-in-part of myco-pending application Serial Number 512,271

flied November 29, 1943, now Patent Number 2,440,477, which in turn is acontinuation-inpart of my application Serial Number 469,037, fliedDecember 14, 1942, now abandoned.

This invention relates to synthetic drying oils and particularly tohighly unsaturated hydrocarbon drying oils.

An object of this invention is a drying oil produced by treatment ofaliphatic hydrocarbons.

Another object of this invention is a hydrocarbon drying oil produced bythe treatment of oleflnic hydrocarbons with hydrogen fluoride.

A further object of this invention is the preparatlon of a hydrocarbonoil having the properties of a drying oil and suitable for use invarnishes, paints, and other protective and decorative coatings.

Broadly, my invention comprises a product formed by reacting ahydrocarbon charging stock in the presence of hydrogen fluoride,separating the reaction mixture into a hydrocarbon phase and a hydrogenfluoride phase, and recovering from the hydrogen fluoride phase an oilhaving drying properties, that is an oil capable of forming thin filmswhich dry {to form protective coatings.

One specific embodiment of this invention comprises a drying oil formedby reacting aliphatic hydrocarbons in the presence of hydrogen fluoride,introducing the reaction mixture into a arating hydrogen fluoride fromsaid hydrogen fluoride layer and recovering substantially fluorine-freehighly unsaturated hydrocarbon material having properties of a dryingoil.

Another embodiment of this invention comprises a drying oil formed byreacting olefin hydrocarbons in the presence of hydrogen fluoride,introducing the reaction mixture into a settling zone to form an upperhydrocarbon layer and a lower hydrogen fluoride layer containing highlyunsaturated hydrocarbon material, separating hydrogen fluoride from saidhydrogen fluoride layer and recovering substantially fluorine-ireehighly unsaturated hydrocarbon material having properties of a dryingoil.

When hydrocarbon reactions are carried out in the presence of hydrogenfluoride catalyst, the used catalyst contains certain valuable organicmaterials. It is this organic material which can be recovered from theused catalyst that is re- 2 ferred to in this specification and claimsas a drying oil. It is believed that some of the hydrocarbon componentsof the drying oil are entrained physically or are dissolved in the usedhydrogen fluoride catalyst while the remainder are combined withhydrogen fluoride in the form of complex compounds. In some cases, theunsaturated hydrocarbon material recovered from" the hydrogen fluoridelayer contains a small proportion of organic fluoride which is removedby suitable puriflcation'treatment as by contacting with activatedalumina, bauxite, aluminum fluoride, etc.

Conversion processes which employ hydrogen fluoride as catalyst and inwhich a catalyst layer containing unsaturated hydrocarbons is formedduring reaction include the polymerization of normally gaseous andnormally liquid olefin hydrocarbons, the alkylation of isoparaflins witholefins, the alkylation of aromatic hydrocarbons with oleflns and thelike.

Although drying oils prepared from olefin containing charging stocks arepreferred, drying oils can also be prepared from other aliphatichydrocarbon charging stocks such as branched chain paraflins. Inprocesses such as those previously mentioned herein, the reactionmixture is allowed to settle and the catalyst layer isseparated from theupper hydrocarbon layer. This catalyst layer contains hydrogen fluorideand the unsaturated hydrocarbons which comprise the drying oil productof my invention. In general, hydrocarbon material recovered from thehydrogen fluoride catalyst layer comprises a series of hydrocarbons ofrather wide boiling range and having more than two double bonds permolecule. The exact composition of the drying oil varies somewhatdepending upon the particular charging stocks and the conditionsemployed in the treating operation.

A typical operation for the production of the drying oils of myinvention may be carried out according to the following description. Ahydrocarbon charge containing normally gaseous and/or normally liquidoleflns is treated in the presence of hydrogen fluoride at suflicientpressure to maintain the reaction mixture in substantially liquid phase,said pressure usually being below about 500 pounds per square inch.Intimate contact between the hydrocarbons and catalyst may be maintainedby some form of agitation, such as mixing, stirring, etc., so as to forma mixture of emulsion of hydrocarbon and hydrogen fluoride. A reactiontemperature of from about 0 to about 300 F. and preferably irom about 50to about 200 F. is usually emwherein hydrogen fluoride is separated bydistillation or other suitable means and recycled to the reaction zone.

The hydrocarbon material remaining after removal of hydrogen fluoridemay be treated in a number oiways to remove any free hydrogen fluorideremaining and to obtain a purified drying oil. A simple method offurther treating the drying oil comprises either steam distillation orvacuum distillation to recover an oil having the desired properties.

alternately, the purified drying oil may be recovered by colngllng thehydrogen fluoride catalyst layer with water. The water serves todissolve any free hydrogen :Tluoride that is presout while theunsaturated hydrocarbon oil rises to the top of the aqueous solution andmay be withdrawn. if desired, the fluidity of the drythe; oil may beincreased by comniingling it with a non=reactive hydrocarbon solventsuch as pentane, and alter thoroughly mixing, the solution is treatedwith a suitable alkaline reagent to neutralize any remaining free acid.The treated mixture is directed to a separation zone in which thehydrocarbon solvent is removed by suitable means such as by distillationand the finished drying oil is recovered, while the hydro carbon solventmay be recycled to further use.

The drying oil product is a sweet smelling liquid ranging in color fromlight yellow to dark brown and drying to a hard film on exposure to air.This drying oil has a wide boiling range of from about no to about 400C... density of from about 0.83 to about (W3, index of refraction offrom about M7 to about 1.53, specific dispersion values of from about125 to about 160 (usually between about 135 and about 145), brominenumber above about 140 (although they vary with the average molecularweight), maleic anhydride values of from about 40 to about 95 (usuallyin the range of from about 50 to about 80) acid numbers below about 3,average number of olefinic double bonds per molecule varying betweenabout 2.5 and about 3.5, of which from about 40 to about 70% areconjugated, and average molecular weights of from about 200 to about400, although the usual average is in the neighborhood of about 300.Some unsaturated hydrocarbon fractions of the drying oil have also beenprepared in which the hydrocarbons have molecular weights as high asabout 150 to as high as about 1000.

Study of the ultra-violet and infra-red absorption spectra of drying oilfractions boiling from about 150 to about 200 C. shows that many ofthese hydrocarbons contain a pair of conjugated double bonds with one ofthese double bonds in a ring of five carbon atoms and the other doublebond in an alkenyl side chain. Thus a cyclopentene ring may be combinedwith a methylene group or a vinyl group. However, some of the drying oilhydrocarbons may also contain a cyclopentadiene ring. The drying oilhydrocarbons which contain a cyclopentenyl ring also contain more thantwo substituent groups but each of these groups is highly substituted.

The higher boiling fractions of the drying oil boiling up to about 4500. contain polycyclic hydrocarbons which are generally bicyclic. In

both the monocycllc and polycyclic hydrocarbons the rlvcrcarbon atomring portions of the molecules are combined with at least two alkyl ortwo unsaturated aliphatic groups. The data obtained on these fractionsindicate that one of the double bonds comprised by the conjugated dlenesystems of the drying oil is within a five- Kill carbon atom ring andthe other double bond is in an alkenyl or allrapolyenyl substltuent.Alkapolyenyl groups that may be present are highly branched and containisolated unsaturation as well as conjugated unsaturation.

Some of the typical hydrocarbons contained in the drying oil mixturesare represented structurally by the following formula:

wherein the radicals R to R are selected from the group consisting ofhydrogen and alkyl, alirenyl and allrapolyenyl hydrocarbon radicals, atleast two of the substituents R to R are hydrocarbon radicals, and notmore than three of R to R represent hydrogen.

Gther constituents of the drying oil are believed to have structuresthat may be represented by the formula ill wherein R to R representmembers of the group consisting of hydrogen and alkyl, alkenyl and a1-lsapolyenyl hydrocarbon radicals, and at least two of the substituents Rto R are hydrocarbon' radicals.

Thus the hydrocarbons represented by each of the above formulae containa ring of live carbon atoms, on alkenyl roup, and at least one pair ofconjugated double bonds per molecule.

The following data are presented to illustrate the preparation of thehydrocarbon drying oil and its characteristic properties.

Example I 438 grams of debutanized polymer gasoline was charged to areactor to which was added 137 grams of hydrogen fluoride. The mixturewas stirred constantly during the conversion which took place at atemperature of 100 C. and a. pressure ranging from 20 to pounds persquare inch. After completion of the reaction, the products weredirected to a settling zone wherein they were separated into an upperlayer comprising essentially saturated hydrocarbons and a lower layercontaining hydrogen fluoride and unsaturated hydrocarbons combinedtherewith. The catalyst layer was withdrawn to a distillation zone fromwhich the hydrogen fluoride was regrams of hydrocarbon drying oil wasrecovered. The properties of the drying oil were as follows:

Molecular weight 326 Index of refraction M 1.4929 Specific dispersion150 Density (di 0.872 Specific refraction 0.333 Color, Gardner BromineNo. 150

Example I! Molecular weight 277 Index of refraction (11 1.4830 Specificdispersion 138 Density (114") 0.856

Specific refraction 0.334 Color, Gardner 12 Bromine No. 191

Example III A drying oil fraction recovered from a catalyst layerproduced when isobutane reacted with butylene under alkylatingconditions in the presence of hydrogen fluoride was found to have thefollowing properties:

Molecular weight 250 Density ((14 0.862 Specific dispersion 137 Index ofrefraction (11. 1.4829 Double bonds per molecule 2.8

when the reaction conditions were varied somewhat on the same chargingmaterial with recycle of used hydrogen fluoride, a drying oil wasrecovered having these properties:

Molecular weight 302 Density (114") 0.902

Specific dispersion 150 Index of refraction (n 1.5052

Double bonds per molecule 3.7

Example IV When isooctene was reacted in the presence of hydrogenfluoride, the drying oil fraction recovered from the catalyst phase hadthese properties:

Molecular weight 330 Density (di 0.893 Specific dispersion 140 Index ofrefraction (11 1.4959

Double bonds per molecule 3.6

A test of the drying properties of the drying oil fractions showed thatthey dried much faster than raw linseed oil with or without a siccative.

Example V 7 line boiling from about 45 to about 200 C. and

0 reaction temperature was increased gradually from 25 C. to C. and thestirring was continued for an additional hour. The reaction mix ture waspermitted to stand quiescent for several minutes. the mixture separatedinto an upper saturated hydrocarbon layer and a lower hydrogen fluoridelayer. The upper layer was washed with caustic soda solution to removesmall amounts of dissolved hydrogen fluoride and the resultant 8.1kilograms of hydrocarbons were iractionally distilled to separatetherefrom a gasohaving an octane number of 82.6.

The lower 7 hydrogen fluoride layer which weighed 16.1 kilograms was alight brown mobile fluid with a density of 0.98 at a temperature of 4 C.The hydrogen fluoride layer was then diluted with waterand a highlyunsaturated hydrocarbon material separated 'from the aqueous hydrogenfluoride. This unsaturated hydrocarbon material was a sweet smelling oiland "amounted to 42.4% byweight of the polymer gasoline originallycharged tov the autoclave. This unsaturated oil had the properties shownin the following table:

Boilingrange to above 400 C. Density (114") 0.863 Index of refraction (n1.4871 Color, Gardner -1 12-13 Molecular weight .a 263 Diene number 85Bromine number Specific dispersion 143 Percent fluorine 0.06 Doublebonds per molecule (average) A portion of the oil with the propertiesshown in the foregoing table was spread as a thin fllm on a glass plateand exposed to air for several days with the result that a non-tacky,tough transparent film resulted which exhibited considerable resistanceto abrasion.

I claim as my invention:

1. A drying oil having a boiling range of from about 150 to about 400C., a density of from about 0.83 to about 0.93, an index of refractionof from about 1.47 to about 1.53, a bromine number above about 140, amaleic anhydride value of from about 50 to about 80, an average of fromabout 2.5 to about 3.5 double bonds per molecule, and a molecular weightof from about 150 to about 1,000 formed by reacting an oleflnichydrocarbon fraction with liquid hydrogen fluoride, and recovering thedrying oil from the hydrofluoric acid layer.

2. A drying oil having a boiling range of from about 150 to about 400C., a density of from about 0.83 to about 0.93, an index of refractionof from about 1.47 to about 1.53, a bromine number above about 140, amaleic anhydride value of from about 50 to about 80, an average numberof oleflnic double bonds per molecule of from about 2.5 to about 3.5 ofwhich from about 40 to about 70% are conjugated, and an averagemolecular weight of from about 200 to about 400 formed by reacting anolefinic hydrocarbon fraction with liquid hydrogen fluoride, andrecovering the drying oil from the hydrofluoric acid layer.

3. A drying oil having a ring of five carbon atoms, an alkenyl group, atleast one pair of conjugated double bonds per molecule, a boiling rangeof from about 150 to about 400 C., a density of from about 0.83 to about0.93, an index of refraction of from about 1.47 to about 1.53, a Tomminenumber above about'l40, a maleic anhydride 75 value of from about'50 toabout 80, an average a number of olefinic double bonds per molecule offrom about 2.5 to about 3.5, and an average molecular weight of fromabout 200 to about 400 formed by -reacting polymer gasoline with liquidhydrogen fluoride, separating the reaction mixture into a hydrocarbonlayer and a used hydrogen. fluoride layer containing organic material,treating said used hydrogen fluoride layer with water, and recovering adrying oil from the resultant re action mixture.

WHEN W. JQHNSTONE.

The to REFERENCES CITED lowing references are of record in thefile ofthis patent:

Number UNITED STATES PATENTS F

